Method and apparatus for multi-radio coexistence on adjacent frequency bands

ABSTRACT

Various methods for controlling an aggressor user equipment (UE) can use two transmission power control loops to mitigate UE-to-UE adjacent carrier frequency band interference to a geographically proximal victim UE. The aggressor UE can select between different transmission power parameters based on two (or more) power values. The usage of any particular power value depends on the time period of the transmission. For example, if a proximal victim UE is scheduled to receive when the aggressor UE is scheduled to transmit, a lower power value may be selected as instructed by a co-scheduler or determined by the aggressor UE. The aggressor UE can also send dual power headroom reports to its serving base station based on the two power values.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/083,105 entitled “Method and Apparatus for Multi-Radio Coexistence onAdjacent Frequency Bands” filed on Apr. 8, 2011 by Colin D. Frank et al.and claims the benefit thereof.

FIELD OF THE DISCLOSURE

This disclosure relates generally to improving coexistence among radiosoperating in adjacent frequency spectrum or bands. These radios may becollocated (i.e., within a single device) or non-collocated (i.e., notwithin a single device).

BACKGROUND OF THE DISCLOSURE

Coexistence refers to the ability for multiple wireless protocols tooperate in or around the same or adjacent time-frequency radio resourceswithout significant degradation to any radio's operation due tointerference. Note that interference may occur at a reception radiofrequency or at any intermediate frequency used within a receivingdevice for the purpose of demodulation. Without coexistence mechanisms,radio frequency interference can cause, amongst other degradations, lossof connectivity, decreased data throughput or reduction in quality ofservice, or increased current drain.

When adjacent radio frequency bands are allocated to different uses,wireless interference can result. In general, there is an elevated riskof wireless interference when a frequency band used for uplinktransmissions is adjacent to a frequency band used for downlinktransmissions; the wireless transmissions in one band can createinterference for wireless receivers operating in the adjacent band.

For example, a user equipment (UE) transmitting at 704-716 MHz (e.g.,the United States Federal Communication Commission Lower 700 MHz band, Band C blocks) can interfere with nearby or collocated user equipmentreceiving at 716-728 MHz (e.g., the United States Federal CommunicationCommission Lower 700 MHz band, D and E blocks). As another example, abase station (eNB) transmitting at 734-746 MHz (e.g., the United StatesFederal Communication Commission Lower 700 MHz band, B and C blocks) caninterfere with a nearby or co-sited base station receiving at 716-728MHz (e.g., the United States Federal Communication Commission Lower 700MHz band, D and E blocks).

The United States (US) Federal Communication Commission (FCC)established common emission spectrum limits and common field strengthlimits for this entire section of spectrum (i.e., 698-746 MHz). Giventhese limits, a common method applied to alleviate interference is tointroduce a “null” or “guard” frequency band between deployed bands thatare sufficient to reduce or avoid interference. However, there is verylittle guard (nominally zero) band between the US FCC Lower 700 MHz Cblock (710-716 MHz) and its adjacent Lower 700 MHz D block (716-722MHz).

As guard bands narrow, improved filtering and/or physical separation oftransmit and receive antennas is commonly used to reduce interferencecaused by adjacent channel leakage (such as harmonics, intermodulationcomponents, parasitic emissions, frequency conversion spuriousemissions, etc.). Although this is feasible at base stations, improvedfiltering and antenna separation may be difficult or prohibitivelyexpensive to implement in user equipment where physical constraints(such as small dimensions which result in low coupling losses betweentransmitting and receiving antennas) and low cost targets apply. Becausemultiple radios can wirelessly interfere with each other in variousways, and effective filtering may not be available at a reasonable cost,coexistence mechanisms should be developed for a variety of collocatedand non-collocated scenarios.

With the continuing emergence of a variety of wireless communicationtechnologies operating in adjacent frequencies, there is an opportunityto provide more effective solutions to mitigate interference andcoexistence problems among collocated and non-collocated radios. Thevarious aspects, features and advantages of the disclosure will becomemore fully apparent to those having ordinary skill in the art uponcareful consideration of the following Drawings and accompanyingDetailed Description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, together with the detailed description below, are incorporated inand form part of the specification, and serve to further illustrateembodiments of concepts that include the claimed invention, and explainvarious principles and advantages of those embodiments.

FIG. 1 shows an example of a spectrum allocation diagram with threeadjacent frequency bands.

FIG. 2 shows an example of user equipment geographical distribution in acoverage region having a spectrum allocation diagram with adjacentfrequency bands similar to FIG. 1.

FIG. 3 shows an example of a time and frequency graph for multi-radiocoexistence.

FIG. 4 shows another example of a time and frequency graph formulti-radio coexistence.

FIG. 5 shows yet another example of a time and frequency graph formulti-radio coexistence.

FIG. 6 shows a further example of a time and frequency graph formulti-radio coexistence.

FIG. 7 shows a yet further example of a time and frequency graph formulti-radio coexistence.

FIG. 8 shows an example block diagram of an orthogonal frequencydivision multiple access (OFDMA) user equipment with an optionalcollocated transceiver.

FIG. 9 shows an example flow diagram for a method for multi-radiocoexistence at a user equipment such as an aggressor UE.

FIG. 10 shows an example block diagram of a co-scheduler forcoordinating communications in power, time, and frequency between twoorthogonal frequency division multiple access (OFDMA) base stations inaccordance with an embodiment.

FIG. 11 shows an example flow diagram for a method for multi-radiocoexistence at a co-scheduler.

FIG. 12 shows an example of a time and frequency graph for multi-radiocoexistence for channel measurements.

FIG. 13 shows an example flow diagram at a co-scheduler for a method formulti-radio coexistence during channel measurements.

FIG. 14 shows a further example of a time and frequency graph formulti-radio coexistence.

FIG. 15 shows an example flow diagram for a method for multi-radiocoexistence using a scheduling delay index.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments. Also, flowchart boxes may berearranged into different sequential orders, repeated, or skipped incertain instances.

The apparatus and method components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments soas not to obscure the disclosure with details that will be readilyapparent to those of ordinary skill in the art having the benefit of thedescription herein.

DETAILED DESCRIPTION

A wide variety of mechanisms can result in adjacent carrier systeminterference. Implementation of a method and apparatus for multi-radiocoexistence allows a co-scheduler to arrange uplink and downlinksubcarrier, subframe, and power assignments in adjacent carrier systemsto mitigate interference by reducing the assignment of radio resourcesor transmission power on radio resources of proximal UEs on differentnetworks that are projected to overlap in time and adjacent frequency.The different networks may also use different radio access technologies(RATs) such as LTE and HSPA, or LTE and GSM. The co-scheduler mayspecifically assign radio resources to each UE to reduce interference ina complete subframe or only a portion of a subframe. The co-schedulermay specifically attempt to reduce interference on a Physical DownlinkControl Channel (PDCCH). The co-scheduler may specifically attempt toreduce interference during a proximal UE's channel measurement timeperiod.

A wireless terminal may help mitigate adjacent carrier systeminterference by complying with transmission instructions from itsserving base station and also by adjusting its transmission power toreduce adjacent carrier system interference when another wirelessterminal is nearby and scheduled to receive transmissions from itsserving base station on an adjacent frequency band or scheduled to makechannel measurements.

Note that in what follows, the concept of an “adjacent band” is onewhere first and second bands (or the frequency portion of time-frequencyradio resources) are fully adjacent or partially adjacent. Here, fullyadjacent means that the first and second frequency bands are disjointwhile partially adjacent means that the first and second frequency bandsmay have common frequency elements. Also the concept of “proximal” islimited to spatial (geographic) proximity and does not include closenessin time or frequency.

FIG. 1 shows an example of a spectrum allocation diagram 100 with threeadjacent frequency bands 110, 120, 130. A “frequency band” refers to thedesignated frequency spectrum portion that a particular transmitter,operating using a particular radio access technology (RAT), is permitteduse. Generally, a frequency band is defined by a governmental entitysuch as the US FCC. Occasionally, this concept is referred to as a“transmission bandwidth configuration” in LTE literature. In somewireless systems, such as LTE, transmission uses at least one subcarrierwithin a frequency band. The allocated transmission sub-carrier(s) maychange over time and frequency.

In this example, paired frequency bands 110, 120 are deployed as 3GPPLong Term Evolution (LTE) frequency division duplex (FDD) uplinkfrequencies and downlink frequencies. Thus, for frequencies within theFDD uplink band 110, mobile stations are transmitting and base stationsare receiving. Meanwhile, for frequencies within the FDD downlink band120, base stations are transmitting and mobile stations are receiving.Note that a mobile station is sometimes called user equipment (UE) or awireless terminal, among other things. Also, a base station is oftencalled an evolved Node B (eNB), or occasionally a network access point(AP), and may also be referred to as a femtocell, picocell, or radioremote head.

In this example, an unpaired frequency band 130 is both adjacent to theupper edge of the FDD uplink band 110 and adjacent to the lower edge ofthe FDD downlink band 120. Note that the x-axis indicates frequency.Depending on how it is deployed, this unpaired spectrum can be used foruplink transmissions, downlink transmissions, or both uplink anddownlink transmissions (at different times). Alternately, this frequencyband 130 can be one part (either downlink or uplink) of a set of pairedFDD frequency bands.

A base station's transmissions in one frequency band may cause receiverdesensitization (desense) at co-sited or nearby base stations that aretuned to receive signals in an adjacent band, especially if an antennasystem of the second base station's receiver is directed toward thefirst base station's transmitting antenna system. For example, if afirst base station (eNB) is transmitting on the FDD downlink 120 (mostnotably but not necessarily exclusively) near the lower-frequency edge,it may interfere 181 with a second base station receiving on theunpaired band 130 near the upper-frequency edge. As another example, ifthe second base station transmits on the unpaired band 130 (most notablybut not necessarily exclusively) near the lower-frequency edge, it mayinterfere 185 with another base station (e.g., the first base station)receiving near the upper-frequency edge of the FDD uplink band 110. Notethat an interfering eNB (also called an aggressor eNB) may be co-sitedwith an interfered-with eNB (also called a victim eNB), or the aggressoreNB and the victim eNB may be in nearby (but not co-sited) locations.

Adjacent band interference can also cause receiver desense in a mobileenvironment as well as a base station environment. When user equipment(UE) is transmitting on the FDD uplink 110 near the upper-frequencyedge, it may interfere 191 with a UE receiver operating in the unpairedband 130 near the lower-frequency edge. Similarly, a UE transmitting inthe unpaired spectrum 130 at the upper-frequency edge can causeinterference 195 with a UE receiving in the FDD downlink band 120 at thelower-frequency edge. Note that an interfering UE (also called anaggressor UE) may be collocated with an interfered-with UE (also calleda victim UE). In other words, the aggressor UE and the victim UE may besubsumed into a single device operating on both the system of the pairedbands and the system of the unpaired band and thus result inself-interference. Alternately, the aggressor UE and the victim UE maybe in nearby (non-collocated) devices. When the aggressor UE and thevictim UE are in separate mobile devices, movement of the devices (one,the other, or both) may increase or reduce interference simply becausethe transmitters and receivers are physically closer or farther awayfrom each other, or the transmitting and receiving antenna systems aredirected toward or away from each other.

Note that mobile devices may also enter into direct or peer-to-peertransmission modes where the concepts of “uplink” and “downlink”operation effectively become those of transmission from a first deviceto a second device, and a second device to a first device. Note alsothat the first and second transmissions may occur in precisely the samefrequency band (such as in a time-division duplex or TDD system) or insubstantially overlapping frequency bands. Finally, one or more of theinterfering transmission or reception activities may include the act ofbroadcast or simulcast operation, where multiple devices receive acommon transmission. All of these scenarios are applicable to thepresent disclosure.

Note that the degree of separation 140, 150 between adjacent bands mayvary. FIG. 1 shows very little separation between the three bands 110,120, 130. Greater separation (i.e., larger guard bands) can supportreasonable-cost filtering and careful antenna system placement to reduceinterference at the mobile stations and base stations. Although notshown in this example, the unpaired frequency band 130 and/or the pairedfrequency bands 110, 120 may include guard bands or sub-bands allocatedfor other purposes. As mentioned earlier, guard bands can assist inreducing interference. With less separation 140, 150 (i.e., smallerguard bands), the filtering at the base stations is more expensive, butusually not cost-prohibitive. With less separation, though, improvedfiltering at the mobile stations becomes very expensive and sufficientantenna system separation may become infeasible.

Although the three bands 110, 120, 130 have been described as anunpaired band 130 situated between the two parts of a paired spectrum110, 120, adjacently interfering bands do not require this particularconfiguration. The three bands may all be unpaired, there may be onlytwo adjacent bands, the center band may be paired with another band (notshown), etc. The issue of adjacent channel interference occurs mostnotably when one frequency handles uplink transmissions and an adjacentfrequency concurrently handles downlink transmissions, although it isalso possible for concurrent adjacent uplink transmissions or concurrentadjacent downlink transmissions to result in interference.

FIG. 2 shows an example of user equipment geographical distribution 200in a coverage region having a spectrum allocation diagram with threeadjacent frequency bands similar to FIG. 1. The region includes a firstbase station 210 for allocating frequency subcarriers and schedulinguplink and downlink communications with wireless user equipmentoperating in the paired frequency bands 110, 120 of FIG. 1. The systemalso includes a second base station 220 for allocating frequencysubcarriers and scheduling uplink and downlink communications withwireless user equipment operating in the unpaired frequency band 130 ofFIG. 1. The second base station is part of an adjacent carrier systemrelative to the first base station (and vice versa). The two basestations 210, 220 cooperate through a backbone interface 235. Thebackbone interference may be an X2 interface, a proprietary interface,or use some other standard such as Ethernet. The backbone interface 235is usually wired but may be wireless. In one embodiment, the first andsecond base stations can be of two different RATs.

A co-scheduler 230 coordinates communications in power, time, andfrequency between the two base stations 210, 220 and their served UEs.The co-scheduler 230 may be physically separate from both base stationsand coupled to both base stations (e.g., through the backbone interface235), or the co-scheduler 230 may be part of one or both of the basestations and coupled to the other base station through the backboneinterface 235 (not shown). The co-scheduler 230 has knowledge of currentand future uplink and downlink assignments (both frequency subcarriersand timing) for each served UE of both base stations. Note that in somearchitectures, the two base stations may be implemented as a single basestation structure (or composite base station), and the co-scheduler maysimply be termed a “scheduler” (or composite scheduler). In oneembodiment, the two base stations (or single composite base station)correspond to two different RATs and the composite scheduler willtranslate the uplink and downlink assignments when determiningco-existence issues such as adjacent channel interference or radiodesense.

The two base stations 210, 220 may be co-sited 240 as optionally shown.Alternately, the base stations 210, 220 may be not co-sited but closeenough to cause adjacent channel interference were coexistence methodsnot used. Co-sited or closely-located base stations help theco-scheduler to more rapidly and conveniently determine information usedas input to scheduling decisions at both base stations, such as timingdifferences (e.g., propagation and multipath) for both base stations,and estimate the coverage areas of both base stations.

Conventional approaches to mitigate interference 181, 185 (see FIG. 1)between the two co-sited (or closely located) base stations 210, 220include stringent site filtering and physical separation of transmit andreceive antenna systems. Also, adjacent channel interference can bereduced by one eNB locating its downlink carrier frequency on a rasterlocation that provides a guard band with respect to the uplink band ofthe other eNB, although this is clearly inefficient in terms of downlinkspectrum.

Further mitigation of interference can be achieved using theco-scheduler 230 implemented to control wireless resource allocation andpower levels in both the paired bands 110, 120 and the unpaired band 130through their respective eNBs 210, 220. The co-scheduler can separatepotentially interfering transmissions and receptions in frequency by,for example, preferentially scheduling Physical Downlink Shared Channel(PDSCH) physical resource blocks (PRBs) in a high frequency portion ofthe unpaired band 130 and/or preferentially scheduling Physical UplinkShared Channel (PUSCH) PRBs in a low frequency portion of the pairedband 110. The co-scheduler can also (or alternately) reduce potentiallyinterfering transmissions by, for example, suppressing or reducing thepower of aggressor UE transmissions (e.g., near the frequency boundarythat is related to the adjacent band interference).

User equipment being served by either base station, perhaps including amobile device being served by both base stations (e.g., collocated UEs),are geographically distributed around the base stations. As a UE movesand gets closer to another UE, interference 191, 195 may result as shownin FIG. 1. UEs may move to create a wide variety of geographicconfigurations, including within a building, inside a moving vehicle,and along streets and sidewalks. As particular UEs move apart, adjacentchannel interference between those two UEs may decrease. At the sametime, adjacent channel interference may increase due to a closerproximity to another UE.

If the interference 191, 195 arises from operation in adjacent bands bythe same device (i.e., collocated UEs), UE mobility does not (of course)reduce the interference 191, 195 but turning on/off any one of thetransceivers would affect interference. Throughout this description,collocated victim and aggressor UEs (or UEs incorporated into a shareddevice) may be within the same device housing or physicalimplementation.

In an example, a first UE 281 transmits in a frequency band to itsserving base station 210 while a second UE 282 is receiving signals inan adjacent frequency band from its serving base station 220. While theUEs 281, 282 are distant from each other (e.g., over 10 meters apart),the transmitted signal of the first UE 281 may not interfere much withreception at the second UE 282 in an adjacent band. When the UEs comeclose to each other (e.g., within 10 meters), however, the transmittedsignal of the aggressor UE 281 may desense the victim UE's receiver suchthat the second UE 282 cannot properly receive and decode the signal inthe adjacent channel from its serving base station 220. Althoughtransmissions from nearby UEs may cause interference with reception by avictim UE 282, transmissions from distant UEs 283, 284 are less likelyto cause significant interference while the second UE 282 is receiving.

In a first scenario, the aggressor UE 281 transmits on the pairedspectrum uplink band 110 while the victim UE 282 receives in theunpaired spectrum 130. In a second scenario, the aggressor UE 281transmits on the unpaired band 130, and the transmissions may interferewith the victim UE 282 receiving on the paired spectrum downlink band120. Again, transmissions from the other UEs 283, 284 that aregeographically separated from the second UE 282 are less likely to causesignificant interference while the second UE 282 is receiving. Notethat, in this document, the aggressor UE is consistently considered thefirst UE 281 (UE1) while the victim UE is consistently considered thesecond UE 282 (UE2). The UEs, however, may be served by either (or both)of the base stations 210, 220, depending on each UE's configurations.

FIG. 3 shows an example of a time and frequency graph 300 formulti-radio coexistence for the aggressor and victim user equipment 281,282 shown in FIG. 2. The x-axis 398 is time and the y-axis 399 isfrequency. The example LTE subframes are 1 ms in duration and may useone or more frequency subcarriers within a frequency band to transmitthe signals. A timing offset T_(O) 397 indicates whether the subframeson each frequency band are synchronized (T_(O)=0) or not (T_(O)≠0). Notethat a timing offset is different from a timing advance. This timingoffset information may be unknown to either UE and/or either eNB. Thistiming offset information, however, is known by the co-scheduler 230 andused when allocating sub-carriers and sub-frames to each UE being servedby the eNBs associated with the co-scheduler. Note that in all of theexample time and frequency graphs shown, the relative timing of signalson frequency resources 110, 120, 130 may vary according to the relativesynchronism of the base stations serving each frequency band 110, 120,130, the relative positions of UE's 281 and 282, as well as otherfactors.

As mentioned with respect to FIG. 2's first scenario, the first UE 281is transmitting during a subframe 310 on an FDD uplink frequency band110 while a second UE 282 is receiving in a subframe 313 on an adjacentfrequency band 130. In this example, the adjacent frequency band 130 isimplemented as an unpaired downlink frequency band, but it could easilybe the downlink band of a pair of FDD frequency bands.

If the two UEs 281, 282 are near each other (e.g., within 10 meters ofeach other, including possibly being collocated within the same device),the signaling or data transmission on the upper subcarrier frequenciesof the transmission in sub-frame 310 can cause interference 315 tosignaling or data regions for the second UE 282 on the lower subcarrierfrequencies of the reception subframe 313 during the overlapping timeperiod when the first UE 281 is transmitting and the second UE 282 isreceiving. Note that, because T_(O)≠0, only part of the sub-frame 313(in time) experiences adjacent channel interference. If T_(O)=0, thenthe entire sub-frame 313 (in time) might experience adjacent channelinterference. Also, depending on the amount of adjacent channel leakageand the “width” of the adjacent band, it is possible that only part ofthe reception sub-frame 313 (in frequency) experiences adjacent channelinterference, as shown. Other situations may have differing amounts ofthe sub-frame 313 (in frequency) that experience adjacent channelinterference, and this frequency amount depends on filtering at theaggressor UE and at the victim UE, antenna separation between theaggressor UE and the victim UE, the power of the transmitted signal fromthe aggressor UE, the configuration of the transmission in frequency atthe aggressor UE, restrictions on UE emission spectra signaled by theeNB, and other factors.

If the two UEs 281, 282 are collocated (i.e., within the same devicewhere it is noted that such a combination of UEs may be denoted as asingle UE that is aggregating two or more of the frequency bands 110,120, 130), the transmitting UE 281 may be aware, through internalsignaling, when the receiving UE 282 is receiving and report thefrequency and timing information to the base station 210 serving theaggressor UE 281, and the co-scheduler 230 can make schedulingadjustments to mitigate interference.

This may be extended to include the situation where the co-scheduler 230has independent and uncoordinated schedulers for the base stations 210,220, and in the extreme case where the base stations 210, 220 areelements of separate and uncoordinated networks. In this instance, basedon the report by the victim UE 282 regarding interference possiblycaused by the aggressor UE 281, the scheduler controlling the victimUE's base station may modify its allocation of time-frequency resourcesto victim UE 282 to reduce interference.

Regardless of whether the UEs are collocated or not, a report by thevictim UE 282 on the interference possibly caused by aggressor UE 281may include statistics on the interference received and attributed toaggressor UE 281, including time and frequency statistics and patterns,power levels, signal to noise ratios, etc. If the UEs are collocated,additional information such as configuration information regarding thebase station 210 serving the aggressor UE 281 can be included. Thisadditional information can include downlink or uplink subframeconfiguration, time or frequency dimension, control channelconfiguration, and other pieces of information that are available to thevictim UE from the aggressor UE.

If the two UEs 281, 282 are not collocated, the UEs may move freelyrelative to each other and thus sometimes be far away from each otherand sometimes be near to each other. When the two UEs 281, 282 are nearto each other, interference 315 is more likely to result.

The UEs 281, 282, 283, 284 may report location information to theirrespective base stations 210, 220, which may be used to help determinewhen UEs may interfere with each other due to proximity. Metrics such aspath loss, transmit power state, relative timing advance, and/or angleof arrival (AoA) estimates may be used to determine the approximatelocation of a UE. Information from another receiver within the UE, suchas satellite navigation system location (e.g., GPS, GLONASS, GALILEO),may be used to determine location information for that UE. Also,location information for potential victim UEs can be sent from a victimUE's base station 220 to a potential aggressor UE's base station 210using the backbone interface 235. Further statistical locationinformation can be used to make location predictions (e.g., frequent UEbehavior due to the locations of roads or an individual's habits andschedule).

When the co-scheduler 230 receives information indicating that there isa potential victim UE 282 (e.g., that a UE 282 receiving in an adjacentband is proximal to a transmitting UE 281), the co-scheduler 230modifies its radio resource allocation and/or power control, to theaggressor UE 281, to the victim UE 282, or to both UEs, to mitigateinterference. For example, the co-scheduler 230 controls the eNB 210serving the aggressor UE 281 to direct the aggressor UE 281 to transmiton a second set of sub-carrier frequencies in a sub-frame 320 when thevictim UE is receiving on an overlapping subframe 323 on the adjacentfrequencies. This second set of sub-carriers excludes one or moresub-carriers near the edge of the frequency band, or in some otherpreferential frequency or time-frequency location. (In some instances,intermodulation effects can result in aggressor frequencies more distantfrom the victim frequency band being significant.) Hence, the aggressorUE 281 will not transmit in the frequency-portion of the paired uplinkband 110 that tends to cause adjacent channel leakage into the unpairedband 130 over the time period 323 when the victim UE is receiving.Alternately, or in addition, the co-scheduler 230 controls the eNB 210serving the aggressor UE 281 to direct the aggressor UE 281 to transmitusing a lower power level in a sub-frame 320 when the victim UE isreceiving during an overlapping subframe 323 on the adjacentfrequencies.

A distant UE (e.g., third UE 283 from FIG. 2) may be assigned the uplinksub-carriers that are vacated by the aggressor UE 281 in the time slot320. The third UE 283 is less likely to cause adjacent channelinterference because the power levels of the signals reaching the victimUE 282 are attenuated due to the distance. Such pairing of UEs 281, 283with large angular separation with respect to the eNB 210, together withbeam-steering using distinct spatial arrays at the eNB 210, can be usedin addition to the co-scheduling methods to further mitigate adjacentband interference. For example, if an eNB 210 uses a Grid-of-Beams (GoB)approach to sub-divide a sector into multiple fixed beams, the eNB cansimply pair UEs from two beams having large spatial isolation.

Additionally or alternately, the co-scheduler 230 can direct the secondeNB 220 to adjust the downlink sub-carriers allocated to the victim UE282 to avoid reception in frequencies near the edge of the band 130closest to the interference source in a subframe 325, 333 that is likelyto experience interference. A distant UE (e.g., fourth UE 284 from FIG.2) may be assigned the downlink subcarriers that are vacated by thevictim UE 282 in the time slot 325, 333. The fourth UE is less likely toexperience adjacent channel interference in subframe 333 because thepower levels of the signals reaching the distant UE 284 from theaggressor UE in subframe 330 are attenuated due to the distance. Thefourth UE is even less likely to experience adjacent channelinterference in subframe 325 due both to distance and a larger frequencyseparation between the aggressor UE 281 subcarriers and the fourth UE284 subcarriers at both subframes 321 and 325.

Note also that, when a specific transmission subframe 317 of theaggressor UE 281 does not overlap in time with the victim UE's receptionsubframes 313, 323, 325, 333, no change in subcarrier frequenciesallocated to the aggressor UE is needed for that subframe 317. Theco-scheduler is aware that the victim UE 282 is not assigned to receiveduring a subframe that overlaps (in time) with transmission sub-frame317. Of course, the co-scheduler or eNB may choose to limit thesubcarrier frequencies allocated to the aggressor UE during the wholetime duration (including subframe 317) when the victim UE is nearby inorder to reduce complexity, signaling overhead, and/or account forpossible timing advance errors.

When the aggressor UE 281 and the victim UE 282 are no longer proximalto each other, the scheduler 230 may return to using any portion (or thefull portion) of sub-carriers in the paired uplink band 110 becauseadjacent band interference is less likely to occur when the UEs aredistant to each other. The same metrics available for determining thatUEs are proximal to each other (e.g., path loss, transmit power state,relative timing advance, angle of arrival (AoA) estimates, GPS location,and/or statistical location information) may also be used to determinethat the UEs are no longer proximal to each other.

Note that the victim UE 282 may be collocated with the aggressor UE 281,in which case the two UEs will always be proximal to each other (exceptwhen one of the transceivers is off).

By reducing the scheduling of time-overlapping transmissions andreceptions in adjacent bands of proximal UEs, adjacent channelinterference can be reduced. By disallowing frequencies near band edgesduring those time periods when adjacent channel interference is likely,due to proximity of aggressor and victim UEs, conventional mobilestation filtering may be acceptable. When the aggressor UE and potentialvictim UE are no longer close to each other, the co-scheduler 230 canallocate frequency subcarriers and subframes without adjacent channelinterference restrictions.

FIG. 4 shows another example of a time and frequency graph 400 formulti-radio coexistence for the aggressor and victim user equipment 281,282 shown in FIG. 2. FIG. 4 is similar to FIG. 3 except that FIG. 4assumes the second scenario described with respect to FIG. 2. In thesecond scenario, an aggressor UE 281 transmits on the unpaired frequencyband 130 and a victim UE 282 receives on an adjacent FDD downlink band120. Although adjacent frequency band 130 is implemented as an unpaireduplink frequency band, it could easily be the uplink band of a pair ofFDD frequency bands. The x-axis 498 is time and the y-axis 499 isfrequency. This is also an LTE example with subframes of 1 ms durationand multiple frequency subcarriers within each frequency band 110, 120,130. (As mentioned previously, other RATs may be used by one or both ofthe wireless networks.) As with FIG. 3, the timing offset 497 can bezero (i.e., the subframes of the aggressor UE and victim UE aresynchronized) or non-zero. This timing offset information is known bythe co-scheduler 230 and used when allocating sub-carriers andsub-frames to each UE being served by the eNBs associated with theco-scheduler.

When the aggressor UE 281 is near the victim UE 282, transmissions onthe upper frequencies of the unpaired band 130 can cause interference415 for the second UE 282 on the lower subcarrier frequencies of areception subframe 413 during the overlapping time period when the firstUE 281 is transmitting and the second UE 282 is receiving. Note that,because T_(O)≠0, only part of the sub-frame 413 (in time) experiencesadjacent channel interference. If T_(O)=0, then none of sub-frame 413(in time) would experience adjacent channel interference. Also,depending on the amount of adjacent channel leakage and the “width” ofthe adjacent band, perhaps only part of the reception sub-frame 413 (infrequency) experiences adjacent channel interference, as shown. Othersituations may have differing amounts of the sub-frame 413 (infrequency) that experience adjacent channel interference, and thisfrequency amount depends on filtering at the aggressor UE and at thevictim UE, antenna separation between the aggressor UE and the victimUE, the power of the transmitted signal from the aggressor UE, and otherfactors such as those previously described.

If the two UEs 281, 282 are collocated (i.e., within the same device),the transmitting UE 281 may be aware, through internal signaling, whenthe receiving UE 282 is scheduled to receive on an adjacent frequency.The transmitting UE 281 can then report the frequency and timinginformation to the base station 220 serving the aggressor UE 281, andthe co-scheduler 230 can make scheduling adjustments to mitigateinterference.

If the two UEs 281, 282 are not collocated, the UEs may move freely withrespect to each other and thus sometimes be far away from each other andsometimes be near to each other. When the two UEs 281, 282 are near eachother, interference 415 is more likely result.

The UEs 281, 282, 283, 284 may report location information to theirrespective base stations 210, 220, which may be used to help determinewhen UEs may interfere with each other due to proximity. Metrics such aspath loss, transmit power state, relative timing advance, and/or angleof arrival (AoA) estimates may be used to determine the approximatelocation of a UE. Information from another receiver within the UE, suchas GPS location, may be used to determine location information for thatUE. Additionally, location information for a potential victim UE can besent from the victim UE's base station 210 to a potential aggressor UE'sbase station 220 using the backbone interface 235.

When the co-scheduler 230 receives information indicating that there isa potential victim UE 282 (e.g., that a UE 282 receiving in an adjacentband is proximal to the transmitting UE 281), the co-scheduler 230controls the eNB 220 serving the aggressor UE 281 to allocate a secondset of sub-carrier frequencies to the aggressor UE 281 on a subframe420, 421 where the victim UE 282 is receiving on an overlapping subframe423 on the adjacent band 120. This second set of sub-carriers excludesone or more sub-carriers near the edge of the uplink frequency band 130closest to the downlink frequency band 120. Hence, the aggressor UE 281will not transmit in the frequency-portion of the unpaired band 130 thattends to cause adjacent channel leakage into the paired downlink band120 during the same time period 423 as when the victim UE is receiving.

A distant UE (e.g., third UE 283 from FIG. 2) may be assigned the uplinksub-channels that are vacated by the aggressor UE 281 in the time slot420, 421. The third UE 283 is less likely to cause adjacent channelinterference because the power levels of the signals reaching the victimUE 282 are attenuated due to the distance. Such pairing of UEs 281, 283with large angular separation with respect to the eNB 210, together withbeam-steering using distinct spatial arrays at the eNB 210, can be usedin addition to the co-scheduling methods to further mitigate adjacentband interference. For example, if an eNB 210 uses a Grid-of-Beams (GoB)approach to sub-divide a sector into multiple fixed beams, the eNB cansimply pair UEs from two beams having large spatial isolation.

Additionally or alternately, the co-scheduler 230 can direct the victimUE's eNB 210 to adjust the downlink sub-carriers allocated to the victimUE 282 to avoid reception in frequencies near the edge of the band 120closest to the interference source in a subframe 425 that overlaps withan uplink subframe 421, 424 of the aggressor UE 281. A distant UE (e.g.,UE 284 from FIG. 2) may be assigned the uplink sub-carriers that areunused by the UE 282 on the FDD downlink band 120. The fourth UE is lesslikely to experience adjacent channel interference in a later portion ofsubframe 425 because the power levels of the signals reaching thedistant UE 284 from the aggressor UE in subframe 424 are attenuated dueto the distance. The fourth UE is even less likely to experienceadjacent channel interference in an earlier portion of subframe 325 dueboth to distance and a larger frequency separation between the aggressorUE 281 subcarriers and the fourth UE 284 subcarriers at both subframes421 and 425.

Note also that, when a specific transmission subframe 417 of theaggressor UE 281 does not overlap in time with the victim UE's receptionsubframes 413, 423, 425, no change in subcarrier frequencies allocatedto the aggressor UE is needed for that subframe 417. The co-scheduler isaware that the victim UE 282 is not assigned to receive during asubframe that overlaps with transmission sub-frame 417. Of course, theco-scheduler or eNB may choose to limit the subcarrier frequenciesallocated to the aggressor UE during the entire time duration (includingsubframe 417) when the victim UE is nearby in order to reducecomplexity, signaling overhead, and/or account for possible timingadvance errors. Note also, that it may be necessary to limit thesubcarrier frequencies allocated to the aggressor UE in order to avoidsaturation or blocking of the victim UE receiver even if the subcarrierfrequencies allocated to the victim UE are restricted.

When the aggressor UE 281 and the victim UE 282 are no longer proximalto each other, the scheduler 230 may return to using any portion (or thefull portion) of sub-carriers in the unpaired band 130 because adjacentband interference is less likely to occur when the UEs are distant toeach other. The same metrics available for determining that UEs areproximal to each other (e.g., path loss, transmit power state, relativetiming advance, angle of arrival (AoA) estimates, and/or GPS location)may also be used to determine that the UEs are no longer proximal toeach other.

Note that the victim UE 282 may be collocated with the aggressor UE 281,in which case the two UEs will always be proximal to each (except whenone of the transceivers is off).

By reducing the scheduling of time-overlapping transmissions andreceptions in adjacent bands of proximal UEs, adjacent channelinterference can be reduced. By disallowing frequencies near band edgesduring those time periods when adjacent channel interference is likelydue to proximity of aggressor and victim UEs, conventional mobilestation filtering may be acceptable. When the aggressor UE and potentialvictim UE are no longer close to each other, the co-scheduler 230 canallocate frequency subcarriers and subframes without adjacent channelinterference restrictions.

FIG. 5 shows yet another example of a time and frequency graph 500 formulti-radio coexistence. FIG. 5 is similar to FIG. 3 in that theunpaired band 130 is configured as a downlink channel adjacent to an FDDuplink band 110, but (like FIG. 3) it could alternately be the downlinkband of a pair of FDD frequency bands. Thus, an aggressor UE 281transmitting on the FDD uplink band 110 in subframe 510 may causeinterference to a potential victim UE 282 receiving in the downlink band130 during subframe 513. Similar to previous graphs, the x-axis 598 istime and the y-axis 599 is frequency.

In the LTE system, Physical Downlink Control Channel (PDCCH) resourcesand reference symbols (such as a cell-specific reference symbol) aretransmitted by a serving eNB 220 during the first few (1-3) symbols of asubframe. (Cell-specific reference symbols are transmitted in symbols 1and 2, but are also transmitted in other symbols in the subframe.) ThePDCCH instructs its served UEs (e.g., victim UE 282) regarding its timeand frequency allocation for the current downlink subframe on a PhysicalDownlink Shared Channel (PDSCH) and for a future uplink subframe on aPhysical Uplink Shared Channel (PUSCH). If the PDCCH is not properlydecoded, the victim UE 282 will have difficulty obtaining its physicalchannel data on the PDSCH and, due to a failure to decode the uplinkgrant, will not be able to transmit its physical channel data on thefuture PUSCH. Thus, the difference between FIG. 3 and FIG. 5 is that thecurrent time and frequency graph 500 is only seeking to mitigateinterference 515 on the PDCCH 514 (rather than trying to mitigateinterference over the entire subframe 513 of the victim UE 282).

As mentioned earlier, PDCCH occurs in the first few (1-3) symbols of asubframe, and thus the timing offset 597, which is known by theco-scheduler 230, can be used to calculate when an aggressor UE's uplinktransmission should be muted 519, 521. Thus, a transmission with PDCCHinterference mitigation occurs in a subframe 520, 550 yet mutes 519, 521transmissions during the time-interval and at subcarrier frequenciesnear where a PDCCH 524, 526 is expected by a proximal UE 282 on asubframe 523, 525 in an adjacent band 130. Alternately, the mutedsection 519, 521 may extend through all frequencies of the aggressorUE's transmission subframe 520, 550. This simplifies implementation ofthe muting to control of a power amplifier in the aggressor UE'stransmitter to fully mute transmission or to partially mute transmissionfor a certain amount of time (e.g., 1-3 symbols) by decreasing thetransmit power of a signal by a given amount (e.g., a certain number ofdBs, a certain percentage of power, below a certain power level, etc.).This method may require special handling of an automatic gain control(AGC) set-point (e.g., AGC tracking may have to be disabled) when theaggressor UE's transmission is altered as proposed.

Note that, due to error correction coding, it may be possible that theaggressor UE can survive the modification to the subframes 520, 550 withPUCCH “symbol puncturing”. In other words, despite the muting 519, 521of the portions of the subframe that may cause interference with thePDCCH 524, 526 being sent in the adjacent channel, the eNB 210 may beable to properly decode the information transmitted in that subframe520, 550.

As illustrated, a PDCCH 526, 562 may occur on less than all of thesubcarriers in a subframe 525, 561. If a subcarrier of the PDCCH 526 ison the edge of the band closer to the interference frequencies, then theco-scheduler 230 and eNB 210 serving the aggressor UE 281 would continueto direct the first UE 281 to mute 521 its transmissions at least duringthe time and frequencies that are likely to cause interference with thePDCCH 526. If PDCCH 562 occurred only in the upper frequency subcarriersof a subframe 561, interference mitigation might not be implemented asshown in subframe 560. These techniques may be used to mitigateinterference for other scheduled and non-scheduled physical channelssuch as PRACH transmission, Sounding Reference Symbol (SRS)transmission, or uplink resources allocated in a semi-persistentlyscheduled (SPS) fashion.

The techniques illustrated in FIGS. 3-5 may be implemented together inany combination. Thus, each physical channel (PDCCH, PDSCH) may besubject to a distinctive interference avoidance strategy. In otherwords, modifications to an aggressor UE's transmissions to enhance PDCCHreception may occur in time and/or frequency, and modifications to anaggressor UE's transmissions to enhance PDSCH reception may occur in adifferent time and/or frequency.

In a collocation situation, where the same device contains the aggressorUE and the victim UE, both the device and the eNB co-scheduler may havecomplete knowledge of the uplink and downlink resource allocation of thedevice and can schedule appropriately. Looking at FIG. 3, for example,the interference 315 would not occur because the eNB co-scheduler canpredict a potential interference and modify the sub-carriers and timingof either UE (or both UEs) within the collocated mobile device beforethe interference could occur.

FIGS. 6-7 show further examples of time and frequency graphs formulti-radio coexistence. In FIGS. 3-5, coexistence is mitigated byallocating a second set of subcarriers to an aggressor UE when there isa proximally-located victim UE operating in an adjacent frequency band.The second set of subcarriers excludes at least one subcarrier from aprevious, first set of transmission subcarriers. In manyimplementations, the excluded subcarrier would be near a frequency bandedge. The excluded subcarrier can be excluded for a complete subframe orfor a portion of a subframe.

In FIGS. 6-7, instead of modifying subcarrier allocations when there isa proximally-located victim UE operating in an adjacent frequency band,an aggressor UE's transmission power is modified when there is aproximally-located victim UE operating in an adjacent frequency band. Ofcourse, both subcarrier and transmission power allocations can bemodified by combining teachings from FIGS. 3-7. And the modifiedtransmission power can be used for a complete subframe or for a portionof a subframe.

FIG. 6 shows a further example of a time and frequency graph 600 formulti-radio coexistence. The x-axis 698 is time and the y-axis 699 isfrequency. In this scenario, the aggressor UE 281 is transmitting on apaired FDD uplink band 110 while a victim UE is transmitting andreceiving (at different times) on an unpaired TDD frequency band 130.Because the frame timing of the TDD and FDD networks may beuncoordinated and hence unsynchronized, the TDD and FDD subframeboundaries (as well as frame boundaries) may not be aligned. In order tosimplify the explanation of FIG. 6, however, the timing offset 697 isshown as zero. As with the other LTE examples, each subframe is of 1 msduration and there are multiple frequency subcarriers within eachfrequency band 110, 120, 130.

A TDD link on the unpaired frequency band 130 includes downlink (D)subframes 640, 660, 662, uplink (U) subframes 650, 652, 670, and special(S) subframes 642, 664. A special TDD subframes includes three sections:a downlink pilot time slot (DwPTS), a guard period (GP), and an uplinkpilot time slot (UpPTS). Thus, a special subframe has both uplink anddownlink components. Presently, LTE has seven TDD downlink/uplinkconfigurations, which define the pattern of D, S, and U subframes withina given frame. The example shown in FIG. 6 shows a victim UE using TDDconfiguration 1. Of course, other TDD configurations may be defined andused.

When an aggressor UE 281 is near the victim UE, aggressor UEtransmissions on the upper frequencies of the paired band 110 can causeinterference 615 for the victim UE on the lower subcarrier frequenciesof a D subframe 640 (or an S subframe reception portion) during theoverlapping time period (e.g., subframes 610, 640) when the first UE 281is transmitting and the victim UE is receiving.

If the co-scheduler 230 receives information indicating that there is apotential victim UE (e.g., that a UE 282 receiving in an adjacent bandis proximal to a transmitting UE 281), the co-scheduler 230 can providea second set of power values to the aggressor UE 281. The co-scheduler230 can also provide to the aggressor UE 281 other UE2 schedulinginformation such as timing offset, TDD downlink/uplink configuration, orscheduled UE2 reception subframe information. In this example, thetiming offset is zero and the TDD downlink/uplink configuration isconfiguration 1. The TDD downlink/uplink configuration or scheduled UE2reception subframe information might be signaled by the co-scheduler 230to the aggressor UE 281 using a configuration index or bit mask (e.g.,0=uplink subframe and 1=downlink or special subframe) of length 10-bitsfor a 10-bit repetitive TDD pattern or of length 5-bits for a 5-bitrepetitive TDD pattern. Of course, other signaling systems and other bitlengths may be used depending on the implementation.

Using the second set of power values and the timing information, theaggressor UE 281 then modifies its transmission power during a timeregion U2 based on when the victim UE is nearby and expected to bereceiving (e.g., during at least part of S subframes 642, 664 and duringD subframes 660, 662). Thus, the interference 617 resulting when usingpower-dimensioned coexistence techniques is at a lower power relative tothe non-mitigated interference 615. When the victim UE is expected to betransmitting (e.g., during subframes 650, 652, 670), the aggressor UE281 may use the previous transmission power parameters (or othertransmission power parameters) to transmit at a different power levelduring time region U1, which results in adjacent channel leakage 619that is not experienced by the proximal victim UE2 as interference.

Thus, the co-scheduler partitions the victim UE2's downlink intomultiple, non-overlapping time subsets, and the aggressor UE uses adifferent set of power values during each time subset U1, U2. Theaggressor UE may implement multiple power loops—each power loop runningseparately for PUSCH, PUCCH, and SRS. Although the time subsets U1, U2are shown in whole subframes, the subsets may be defined as portions ofsubframes (e.g., slots or half-subframes, LTE symbols, etc.). Althoughthere are two time subsets U1, U2 shown in this example, more than twotime subsets may be implemented and, consequently, more than two sets ofpower values and more than two power loops. In one instance, theaggressor UE's eNB can maintain the power control loop for region U1identical to that in legacy systems such as LTE Rel-8/9/10. However,because legacy-valued power transmissions during region U2 are likely tode-sense TDD downlink reception at the victim UE2, the aggressor UEtransmit power during region U2 can be set to a value smaller than theaggressor UE transmit power during region U1.

FIG. 7 shows a yet further example of a time and frequency graph formulti-radio coexistence using a second set of uplink power controlparameters. Like FIGS. 3 and 5, adjacent frequency band 130 isimplemented as an unpaired downlink frequency band (or band 130 could bethe downlink band of a pair of FDD frequency bands). The x-axis 798 istime and the y-axis 799 is frequency. The example LTE subframes are 1 msin duration and may use one or more frequency subcarriers within afrequency band to transmit the signals. A timing offset T_(o) 797indicates whether the subframes on each frequency band are synchronized(T_(O)=0) or not (T_(O)≠0). In this example, the timing offset is set tozero for the sake of simplicity.

As shown, a victim UE 282 is assigned downlink subframes 740, 742, 750in frequency band 130 while an aggressor UE 281 is assigned uplinksubframes 710, 712, 720, 722, 724, 726, 728, 730 in adjacent frequencyband 110. Without mitigation techniques, the aggressor UE'stransmissions during subframe 710 may cause significant interference 715to a proximal victim UE's receptions in overlapping subframe 740.

When the co-scheduler 230 receives information indicating that there isa potential victim UE (e.g., that a UE 282 receiving in an adjacent bandis proximal to a transmitting UE 281), the co-scheduler 230 provides asecond set of power values to the aggressor UE 281. Alternately, thesecond set of power values could have been provided earlier to theaggressor UE and the co-scheduler instructs the aggressor UE on when touse the second set of power values. The co-scheduler 230 also providesUE2 downlink scheduling information (possibly including timing offsetinformation) to the aggressor UE 281. In this example, the timing offsetis zero and the victim UE 282 is scheduled to receive during subframes742, 750. Among other possibilities, the UE2 downlink schedulinginformation may be signaled by the co-scheduler 230 to the aggressor UE281 using a bit mask (e.g., 0=no downlink subframe scheduled and1=downlink subframe scheduled) for a given number of subframes into thefuture.

The aggressor UE 281 then modifies its transmission power during regionU2 based on the second set of power values when the victim UE is nearbyand is expected to be receiving (e.g., during subframes 742, 750). Thus,the interference 717 resulting when using power-dimensioned coexistencetechniques is at a lower power relative to the non-mitigatedinterference 715. When the victim UE is not expected to be receiving inthe adjacent band 130 (e.g., during subframes 760, 762, 764, 766, 768),the aggressor UE 281 may use the previous transmission power parameters(or other transmission power parameters) to transmit at a differentpower level within time region U1, which results in adjacent channelleakage 719 that is not experienced by the victim UE as interference.

In more detail, the aggressor UE1 sets a PUSCH transmit power in timeregion U1 given by:

${{P_{{PUSCH},{{loop}\; 1}}(n)} = {\min\left\{ \begin{matrix}{{P_{CMAX}(n)},} \\\begin{matrix}{{10{\log_{10}\left( {M_{PUSCH}(n)} \right)}} + P_{{O\_ PUSCH},{{loop}\; 1}} + {\alpha_{{loop}\; 1} \cdot {PL}} +} \\{{\Delta_{{TF},{{loop}\; 1}}(i)} + {f_{{loop}\; 1}(i)}}\end{matrix}\end{matrix} \right\}}},$and a PUSCH transmit power during time region U2 given by:

${P_{{PUSCH},{{loop}\; 2}}(n)} = {\min\left\{ \begin{matrix}{\mspace{140mu}{{P_{CMAX}(n)},}} \\{{10{\log_{10}\left( {M_{PUSCH}(n)} \right)}} + P_{{O\_ PUSCH},{{loop}\; 2}} +} \\{\mspace{20mu}{{\alpha_{{loop}\; 2} \cdot {PL}} + {\Delta_{{TF},{{loop}\; 2}}(i)} + {f_{{loop}\; 2}(i)}}}\end{matrix} \right\}}$where P_(PUSCH, loop j)(n) is the PUSCH transmit power in uplinksubframe n that belongs to region Uj (j=1, 2), P_(CMAX)(n) is theconfigured maximum transmit power, M_(PUSCH) (n) is the bandwidth of thePUSCH resource assignment in subframe n, P_(O) _(—) _(PUSCH, loop j) isthe PUSCH power offset configured by higher layers, α_(loop j) is thefractional power control coefficient configured by higher layers, PL isthe path loss associated with the eNB-UE link, Δ_(TF, loop j)(i) is thepower control delta (associated with transmitting UCI [uplink controlinformation] on an uplink shared channel (UL-SCH) configured by higherlayers, and f_(loop j)(i) is the power term when power controlaccumulation is enabled for subframe n when subframe n happens to be thei-th subframe since accumulation was reset.

In the above equations, i is the number of subframes over which poweroffsets derived from transmit power control (TPC) commands wereaccumulated. Therefore, i=n−n_(RESET) where, n_(RESET) is the subframeindex of the subframe where power accumulation due to TPC commands waslast reset. The TPC commands are transmitted in downlink controlinformation (DCI) transported over PDCCH. The serving cell can transmita TPC command applicable to loop 1 on subframe (n-k) where for examplek=4 or k=6. In one embodiment, the TPC command is included in PDCCH withDCI format 0 for serving cell c or is jointly coded with other TPCcommands in PDCCH with DCI format 3/3A whose CRC parity bits arescrambled with TPC-PUSCH-RNTI. The TPC command may include an indicatorthat signals which of the two power control loops, loop 1 or loop 2, theTPC command must be applied to. Upon receiving the TPC command, the UEapplies the closed-loop power control update:f _(loop j)(i)=f _(loop j)(i−1)+δ_(PUSCH,loop j)(i−K _(PUSCH))where δ_(PUSCH, loop j) is determined based on the TPC commandapplicable to loop j and K_(PUSCH)=4 or 6.

This concept is applicable to other uplink transmissions such as PUCCH,SRS, Demodulation Reference Signal (DM-RS), etc. Thus, similar equationscan be written down for regions U1 and U2 for PUCCH, SRS, and DM-RStransmissions.

The aggressor UE1 computes a P_(CMAX) applicable to subframe n based onwhether or not there is a simultaneous transmission of PUSCH on anotherset of uplink resources, whether or not there is a simultaneous PUCCH orSRS transmission, whether or not there is power back off (denoted by“Maximum Power Reduction (MPR)” or “additional maximum power reduction(A-MPR)”) associated with a higher order modulation (16 QAM, 64 QAM, 256QAM), and/or the amount of out-of-band and spurious emissions.

Additionally, the aggressor UE1 may compute separate power headroomreports (PHRs) for regions U1 and U2 based on the U1 and U2 P_(CMAX)values and the computed uplink transmit power, because the respectiveuplink transmit powers may be different:PH _(loop 1)(n)=P _(CMAX)(n)−{10 log₁₀(M _(PUSCH)(n))+P _(O) _(—)_(PUSCH,loop 1)+α_(loop 1) ·PL+Δ _(TF,loop 1)(i)+f _(loop 1)(i)}PH _(loop 2)(n)=P _(CMAX)(n)−{10 log₁₀(M _(PUSCH)(n))+P _(O) _(—)_(PUSCH,loop 2)+α_(loop 2) ·PL+Δ _(TF,loop 2)(i)}PHRs for each loop may be triggered independently, and a single bit candistinguish between the PHRs of two loops. Also, the aggressor UE mayuse a lower modulation and coding scheme (MCS) during time region U2,which may help to compensate for the lower uplink transmission power.

In “virtual PHR reporting”, an aggressor UE can be configured to computeand transmit PHR on a subframe for a given component carrier even whenit is not transmitting PUSCH on that subframe in that component carrier.For the purpose of PHR computation, the UE 281 assumes a certainreference resource (an allocation of a certain size, RB start location,etc.) in its PHR computation.

Note that FIGS. 3-7 provide scenarios for mitigating interference whencollocated or proximal UEs are operating in adjacent frequency bands.FIGS. 3-4 describe a frequency-and-time dimensioned mitigation, FIG. 5describes another type of frequency-and-time dimensioned mitigation, andFIGS. 6-7 describe a power-and-time control dimensioned mitigation.These different types of mitigation can be used separately or inconjunction and independently applied to various physical channels(e.g., PDCCH, PUCCH, PDSCH, PUSCH, and SRS). The interference mitigationis managed by a co-scheduler 230 in cooperation with one or more of thecollocated or proximal UEs.

A timing advance (TA) command that is decoded in a Medium Access Control(MAC) control element (CE) in subframe n can be applied by the UE in aUL transmission on subframe n+k where for example k=6. Therefore, it ispossible that subframes (n+k−1) and (n+k) are partially overlapping. Incase of a potential overlap, the UE may to truncate the transmission ofthe overlapping portion on either subframe (n+k−1) or subframe (n+k).

This above method of using two PC loops can be used to protect a secondRAT such as UTRA, IEEE 802.11 (WiFi), Bluetooth (BT), etc. For example,the aggressor and the victim may be the same wireless terminal andin-device interference issue can arise where a LTE UL transmission mayinterfere with UTRA or WiFi reception. For example, in FIG. 6, subframeswithin power region U2 can be “reserved” for use by the victimtechnology. The interference during power region U2 from a potential LTEUL transmission can be mitigated by reducing transmit power on subframeswithin power region U2 by applying the above embodiment.

The two power control loops (i.e., loop 1 and loop 2) can be appliedseparately to each component carrier when multiple carriers areaggregated on the uplink. In principle, we could have two power controlloops each per UL component carrier.

FIG. 8 shows an example block diagram of an orthogonal frequencydivision multiple access (OFDMA) user equipment 800 with an optionalcollocated transceiver 870. The user equipment could be the aggressor UE281, the victim UE 282, a single mobile device containing collocatedaggressor and victim UEs, or any other UE 283, 284 shown in FIG. 2. TheUE block diagram is greatly simplified to focus only on details that arepertinent to multi-radio coexistence.

The UE 800 includes a battery 810 or other portable power source, acontroller 820 for controlling the various components of the UE 800, anda memory 830 for storing programs and data for the UE 800 and itscontroller 820. The UE 800 also includes a user interface 840 includingcomponents such as a loudspeaker, a microphone, a keypad, and a display.

A first transceiver 860 is coupled to the other components through a bus890. The first transceiver can be coupled to a multi-port ormulti-antenna MIMO antenna system 865 for LTE signaling. Optionally, theUE can include a second transceiver 870 with a shared or secondarymulti-antenna system 875 and also responsive to a specific radiotechnology or modulation type such as LTE, HSPA, or OFDMA. When twotransceivers are within a single device, the first and secondtransceivers are collocated. If the transmitter of the first transceiver860 is transmitting on a frequency that is adjacent to an operatingfrequency of the receiver of the second transceiver 870, interference islikely to result unless coexistence tactics are used. The controller 820is aware of the uplink and downlink operational frequencies,transmission power parameters, and timing of both transceivers, and thecontroller 820 can direct the first transceiver 860 to inform itsserving base station regarding the need for coexistence between thecollocated transceivers.

Even if a victim transceiver is not collocated with an aggressortransceiver, the victim transceiver can provide location information(e.g., path loss, transmit power state, relative timing advance, angleof arrival (AoA), and/or GPS location) to its serving eNB, and that eNBcan transfer the location information to the aggressor UE's eNB todetermine the proximity of the aggressor UE to the victim UE.

The serving eNB may also deliver UE2 scheduling information and multiplesets of power control parameters to assist the UE in mitigatinginterference between UE1 and UE2. The scheduling information for boththe UE1 and UE2 are determined by a co-scheduler 230 that is coupled tothe serving eNB 210 of the aggressor UE 281 and to the serving eNB 220of the victim UE 282. See FIG. 2.

FIG. 9 shows an example flow diagram 900 for a method for multi-radiocoexistence at a user equipment such as an aggressor UE. This flowdiagram 900 may be implemented using the memory 830, controller 820, andOFDMA transceiver 860 components of the OFDMA user equipment 800 shownin FIG. 8.

Initially, the OFDMA user equipment receives 910 from its serving eNB anallocation of a first set of subcarrier(s), time periods(s), andtransmission power parameter(s). LTE generally allocates more than onesubcarrier on one or more subframes and uses multiple transmission powerparameters, but other RATs may allocate these three elements in aslightly different manner. Next, the UE1 determines 920 a firsttransmission power value from the transmission power parameters andtransmits 930 on the subcarrier(s) of the first set, in one or more timeperiods of the first set, based on the first transmission power value.

In this flow diagram, the UE1 optionally reports 940 geographic positioninformation. This geographic position information can be obtained usinga positioning receiver such as a GPS receiver or an Assisted-GPSreceiver. This reporting step 940 may occur at a different sequence inthe flow diagram (e.g., anytime prior to or during steps 910, 920, 930)or may be omitted. For example, this reporting step may be omitted whenthe aggressor UE's serving eNB can determine geographic positioninformation.

This initial set of steps 910, 920, 930, 940 may repeat in accordancewith standard wireless signaling procedures. If, in the wireless networkinfrastructure, the co-scheduler 230 has detected a proximal potentialvictim UE operating on an adjacent frequency band, it may take steps tomitigate interference between the UE1 transmissions and the UE2'sadjacent frequency band receptions.

At this point, the UE1 receives 950 an allocation of a second set ofsubcarrier(s), time period(s), and transmission power parameter(s). Thissecond set is similar to the first set; however, the second set takesinto account a proximal UE2 operating on an adjacent frequency band. TheUE1 may optionally receive 960 some UE2 scheduling information that mayindicate when the UE2 is scheduled to receive on the adjacent frequencyband.

Using the transmission power parameters from the second set, the UE1determines 970 a second transmission power value. Optionally, the UE1also determines 975 a third transmission power value from thetransmission power parameters of the second set. If the transmissionpower parameters of the second set are dual transmission powerparameters, then the calculation of a third transmission power value isappropriate.

Based on the allocation information from step 950 and/or the UE2scheduling information from step 960, the UE1 determines 980 whether aparticular time period (e.g., subframe or subframe portion) of thesecond set belongs to a region U1 as shown in FIGS. 6-7.

If the particular time period belongs to region U1, the UE1 transmits983 on the subcarriers of the second set, during the particular timeperiod, based on the first (or third) transmission power value. If thereis no third transmission power value, then the UE1 transmits based onthe first transmission power value previously determined in step 920. Ifthe particular subframe does not belong to region U1 (e.g., the subframebelongs to region U2), the UE1 transmits 985 on the subcarriers of thesecond set, in the particular time period, based on the secondtransmission power value.

Optionally, the UE1 can determine separate power headroom reports forthe separate regions U1, U2. The UE1 determines 991 a first powerheadroom report for the particular time period based on the first (orthird) transmission power value and transmits 993 the first powerheadroom report to its serving base station. The UE1 determines 995 asecond power headroom report for the particular time period based on thesecond transmission power value and transmits 997 the second powerheadroom report to the serving base station. Power headroom reports maybe sent independently of each other and a bit-field may be added to eachreport to indicate whether the power headroom report applies to regionU1 or region U2.

After transmitting on the time periods of the second set, the secondaryset of steps 950, 960, 970, 975, 980, 983, 985, 991, 993, 995, 997 mayrepeat as long as the co-scheduler 230 detects a proximal potentialvictim UE operating on an adjacent frequency band and is directing theUE1 to help mitigate interference. The flow returns to step 910 when theUE1 no longer receives a set of subcarriers, time periods, andtransmission power parameters that attempts to mitigate interference ata proximal victim UE because, for example, the co-scheduler hasdetermined that there are no longer any nearby UEs receiving on anadjacent carrier frequency band.

In this manner, the UE1 complies with subcarrier, time period, and powerinstructions received from its serving eNB in order to mitigateinterference to a proximally-located potential victim UE2 operating inan adjacent carrier frequency band.

FIG. 10 shows an example block diagram 1000 of a co-scheduler forcoordinating communications in time and frequency between two orthogonalfrequency divisional multiple access (OFDMA) base stations 1010, 1020 inaccordance with an embodiment. The base stations could be the FDD basestation 210 and the unpaired system base station 220 shown in FIG. 2.Alternately, one or more of the base stations 1010, 1020 could be adifferent type of base station. The co-scheduler and base station blockdiagrams are greatly simplified to focus only on details that arepertinent to multi-radio coexistence.

Each base station 1010, 1020 includes a transceiver 1013, 1023 with apower amplifier 1016, 1026 and an antenna system (not shown) havingmultiple antennas. The base station may include multiple sectors, and/ormultiple transceivers. The base stations serve an overlapping geographicarea and operate on at least one adjacent frequency band. Thetransceivers 1013, 1023 are controlled in part by a co-scheduler 1030that may be co-located with either base station, distributed within bothbase stations, or located outside of the base stations 1010, 1020 andcoupled to the base stations. The base stations 1010, 1020 also havebackbone interfaces 1018, 1028 that are coupled to the other basestation serving an overlapping geographic area and operating on at leastone adjacent frequency band. With a 3GPP LTE network, the backbone 1035may be an X2 interface, a different type of standard interface, or aproprietary interface.

The co-scheduler 1030 includes a proximal interference assessor 1033 anda time-frequency-power resource allocator 1037. The proximalinterference assessor 1033 receives first UE (e.g., aggressor UE1)location information 1041 from the first eNB 1010 and receives second UE(e.g., victim UE2) location information 1043 from the second eNB 1020.The UE location information can be generated within the UE itself (e.g.,via stand-alone GPS) and transmitted 1091, 1093 to the serving eNB torelay to the co-scheduler 1030, can be generated with cooperation of theUE and the eNB (e.g., via assisted GPS and/or angle of arrivalinformation and/or path loss, transmit power state, relative timingadvance) and sent to the co-scheduler 1030, or can be produced by theeNB without the assistance of the UE (e.g., angle of arrival informationand/or path loss, transmit power state, relative timing advance). Basedon the location information 1041, 1043, the proximal interferenceassessor 1033 can determine whether the two UEs are proximal and thecircumstances under which their downlink and uplink assignments arelikely to cause interference.

The time-frequency-power resource allocator 1037 receives thetime-frequency constraints from the proximal interference assessor 1033,which are based on the proximity information of the two UEs, andschedules UE1 wireless resources and UE2 wireless resources in a mannerthat mitigates proximal UE interference. For example, thetime-frequency-power resource allocator 1037 may reduce the sub-carriersassigned to one or both of the UEs during an overlapping time frame, maynot assign certain sub-frames to one or both of the UEs, and/or mayprovide dual power control instructions to one or both of the UEs duringcertain symbols, slots, or subframes. These proximity constraints 1034may be in addition to other, pre-existing scheduling constraints. Thetime-frequency-power resource allocator 1037 then sends the UE1scheduling information 1045 to the UE1's serving base station 1010 andthe UE2 scheduling information 1047 to the UE2's serving base station1020. Based on the scheduling information, the base station transceivers1013, 1023 and their respective power amplifiers 1016, 1026 arecontrolled to transmit and receive signaling and data.

Optionally, the time-frequency-power resource allocator 1037 can sendUE2 scheduling information 1049 to the first eNB 1010. This informationcan be relayed 1099 to the UE1 1081 so that the UE1 can make decisionsregarding whether to transmit and/or transmit power based on known UE2scheduling information. This will be described in more detail later. Ofcourse, standard uplink and downlink signaling and data 1095, 1097 aretransmitted to and from each UE 1081, 1082 to its serving eNB 1010, 1020in compliance with the assigned scheduling information. In addition tothe standard power control parameters, a second set of power controlparameters 1096 may be signaled from the first eNB 1010 to the UE1 1081,and the UE1 may provide a second set of headroom reports to the firsteNB. These optional communications 1096, 1099 are applicable toimplementations of coexistence that use UE2 timing information and/orpower-control-dimensioned interference mitigation.

Regarding power control, the co-scheduler 1030 may configure a loweruplink transmit power in one or more proximal aggressor UEs duringcertain scheduled times. For example, within this embodiment, P_(O) _(—)_(PUSCH, loop l) can be configured to be much lower than P_(O) _(—)_(PUSCH, loop 2) (i.e., back off power during region U2 relative toregion U1) resulting in a less overall interference to the victim UE2'sdownlink subframes or subframe portions. For dynamically scheduledaggressor UE 1081 PUSCH transmissions, the co-scheduler 1030 canschedule a lower MCS in UL-SCH on subframes in region U2 to compensatefor the reduced uplink transmit power. In cases of pre-configuredtransmissions such as SPS, periodic PUCCH, and SRS, the aggressor UE mayimplement some predetermined rules to compensate for the lower transmitpower during region U2. For example, the aggressor UE may autonomouslytransmit using a lower MCS if SPS transmissions are ongoing. Theaggressor UE may transmit using an alternate uplink control information(UCI) format with a higher code protection (i.e., lower code rate)during region U2.

The eNB-controlled Δ_(TF) and δ_(PUSCH) variables are separatelysignaled for the two power control loops of the aggressor UEimplementing power-dimensioned interference mitigation techniques. In afurther alternative, a maximum power reduction (MPR) or an additionalmaximum power reduction (A-MPR) can be signaled for either or both ofthe power control loops. To minimize signaling overhead, the MPR/A-MPRfor the second loop can be signaled as an offset relative to theMPR/A-MPR for the first loop.

In another embodiment, only relatively few parameter offsets aresignaled to establish the second power control loop. For example, anoffset is signaled for one of: P_(O) _(—) _(PUSCH,c)(p), PL_(c),Δ_(TF,c)(i). P_(O) _(—) _(PUSCH,c)(p) is a parameter composed of the sumof a component P_(O) _(—) _(NOMINAL) _(—) _(PUSCH,c)(p) provided fromhigher layer signaling for p=0 and 1 and a component P_(O) _(—) _(UE)_(—) _(PUSCH,c)(p) provided by higher layer signaling for p=0 and 1 forserving cell c. For PUSCH (re)transmissions corresponding to asemi-persistent grant then p=0, for PUSCH (re)transmissionscorresponding to a dynamic scheduled grant then p=1, and for PUSCH(re)transmissions corresponding to the random access response grant thenp=2. P_(O) _(—) _(UE) _(—) _(PUSCH,c)(2)=0 and P_(O) _(—) _(NOMINAL)_(—) _(PUSCH,c)(2)=P_(O) _(—) _(PRE)+Δ_(PREAMBLE) _(—) _(Msg3), wherethe parameter preambleInitialReceivedTargetPower (P_(O) _(—) _(PRE)) andΔ_(PREAMBLE) _(—) _(Msg3) are signaled from higher layers.

Pk is the downlink path loss estimate calculated by each UE for itsserving cell c in dB. And PL_(c)=referenceSignalPower−higher layerfiltered RSRP [reference signal received power], wherereferenceSignalPower is provided by higher layers, RSRP is defined inLTE technical specification 36.214 for the reference serving cell, andthe higher layer filter configuration is defined in LTE technicalspecification 36.331 for the reference serving cell. Thus, measured RSRPis filtered by higher layers in the UE in accordance with LTE technicalspecifications. The serving cell chosen as the reference serving celland used for determining referenceSignalPower and higher layer filteredRSRP is configured by the higher layer parameterpathlossReferenceLinking which is signaled from the serving basestation. The case of multiple serving cells for a UE in LTE occurs forcarrier aggregation where the UE is configured to be scheduled on morethan one carrier (i.e., more than one serving cell where each servingcell may also be referred to as a TDD carrier or FDD carrier pair or asa component carrier) in a given subframe. Hence, for carrieraggregation, one of the serving cells must be chosen as the referenceserving cell for power control purposes as described above. The offsetto one of the power control parameters, which could be used to form asecond power control loop, could be implemented for each serving cellsuch that each serving cell has a second power control loop.Alternately, the offset could be used for just one of the serving cells(e.g., the reference serving cell or a special serving cell called theprimary serving cell). In the case of a single, primary serving cell,physical uplink control channel power control (PUCCH) is only supportedon the primary serving cell.

The co-scheduler 1030 may enable this dual power control loopimplementation in the aggressor UE 1081 when it detects that there arepotential victim UEs in the vicinity of the aggressor UE (e.g., bygeo-location, by a report or trigger generated by the victim UE 1082 orvictim UE's serving eNB 1020, or by some other means).

When the proximal interference assessor 1033 receives updated locationinformation 1041, 1043 indicating that the UEs are no longer proximal toeach other, it may lift the proximity constraints from thetime-frequency-power resource allocator 1037. Alternately, the proximityconstraints 1034 may be set in place for a predetermined amount of timeand expire—unless updated location information 1041, 1043 indicates thatthe predetermined amount of time needs to be reset.

Note that the proximal interference assessor 1033 is a logical functionthat may be incorporated as part of the time-frequency-power resourceallocator 1037 or another part of the co-scheduler 1030. As mentionedpreviously, the co-scheduler 1030 can be implemented in a distributedfashion where part of the implementation resides in the aggressor UE'sserving eNB 1010 and part of the implementation resides in the victimUE's serving eNB 1020 supported by inter-eNB signaling 1035.

In some power control coexistence implementations, the aggressor UE'seNB 1010 can back off aggressor UE uplink power during time region U2based on some inter-eNB signaling 1035 triggers. For example, the victimUE 1082 can detect, measure, and report the presence of an aggressor UE1081 and the associated interference level to its serving eNB 1020. Thevictim UE's serving eNB 1010 can relay this report to the aggressor UE'sserving eNB 1010 along with some UE2 timing information (e.g., subframeand/or frame timing). The aggressor eNB 1010 can then use this report tomodify the uplink power control loop applicable to region U2 to protectthe D and S subframes of proximal TDD victim UEs and the PDSCH ofproximal FDD victim UEs. This way, power back off during time region U2is applied by the aggressor eNB 1081 only when there are adjacentcarrier frequency band victim UEs 1081 receiving in the vicinity of anaggressor UE.

In the limit, the eNB 1010 associated with the aggressor UE 1081 couldsimply avoid scheduling aggressor UE transmissions in the subframescorresponding to some or all of the downlink subframes associated withthe victim UE either by explicit signaling or by signaling theappropriate P_(O) _(—) _(PUSCH, loop j) value (say, set to “negativeinfinity”) which effectively suspends the uplink transmissions onsubframes during region Uj.

In the power control loop embodiments described, there can be a switchbetween the two different open loop power levels depending on whetherthe aggressor UE's transmission and the victim UE's reception arescheduled for a given subframe. An indicator, or even a single bit, canbe used in the grant to explicitly specify one of two open loop powerlevels on the uplink. Alternately, given the victim UE's schedulinginformation, the aggressor UE can select between the two or more sets oftransmission power control parameters based on the region (U1 or U2)during which it is transmitting. The uplink power levels can be reducedon specific subframes (e.g., during region U2) with potentially smallperformance losses.

The transmission power levels on the uplink (aggressor) channel or thepower level difference between the uplink (aggressor) and downlink(victim) channels can be reduced to help alleviate the desensing causedby the uplink and downlink channels. This can be implemented by theserving base station signaling an energy per resource element (EPRE)setting applicable to a set of resource elements where the resourceelements are part of the subcarriers being used for uplink transmission.An indicator can be used on the uplink scheduling grant to set theuplink power values during the regions U2. For example, the indicatorcan be an enhanced Transmission Power Setting (TPS) that is signaled tothe aggressor UE in addition to a legacy transmission power controlcommand through the downlink control information (DCI). The TPS could bea one-bit field that explicitly requests the UE to select a particularone of the two open loop uplink power levels. The TPS indicator could bea transmission power control (TPC) command to modify the power states ofthe UE for a region U2 in addition to (or in place of) higher-layersignaling in either of the previously presented embodiments.

FIG. 11 shows an example flow diagram 1100 for a method for multi-radiocoexistence at a co-scheduler, such as the co-scheduler 1030 in FIG. 10,when proximal UEs, such as aggressor UE 1081 and victim UE 1082 in FIG.10, are expected to experience adjacent channel interference. Ingeneral, the co-scheduler 1030 controlling both base stations 1010, 1020will jointly assess the traffic that is available to be scheduled fortransmission by both the paired frequency band eNB 1010 and the unpairedfrequency band eNB 1020, and by taking into account the possibility formutual interference between the proximal first and second UEs, theco-scheduler 1030 will modify its scheduling strategy. In oneembodiment, the co-scheduler is scheduling and assigning resources formobile stations via their respective serving base stations that belongto different RATs. In this case, the scheduler must address differencesin time and frequency of the resource allocation used for each RAT indetermining how to mitigate adjacent channel interference.

In another embodiment (that may be used in conjunction with thetime-and-frequency allocation embodiment), the scheduler directs the eNBto use power control techniques to mitigate adjacent channelinterference. For example, using teachings from the above embodiments,the power levels of subcarriers within a frequency span for a subframecan be adjusted. This can be implemented by the serving base stationsignaling an energy per resource element (EPRE) setting applicable to aset of resource elements where the resource elements are part of thesubcarriers being used for uplink transmission.

Initially, the co-scheduler 1030 allocates 1110 a first set ofsubcarriers to the uplink channel of a first UE 1081. This allocationdoes not contemplate any adjacent channel interference restrictions ineither time or frequency. Of course, other restrictions may exist basedon network loading, the number of UEs being served by the eNB, etc.Because this UE1 is allocated transmission frequencies, it is considereda potential aggressor UE 281.

Next, the co-scheduler 1030 detects 1120 whether another UE is operatingproximal to the aggressor UE 281. This detection function can beperformed by the proximal interference assessor 1033 shown in FIG. 10. Adetection of a proximal victim UE may occur through information sentthrough a backbone interface of the eNBs serving the aggressor andvictim UEs. The UE2 may have a downlink channel that is adjacent to theuplink channel of the aggressor UE and thus may experience interferencefrom the aggressor UE's transmissions. Thus, this second UE isconsidered a potential victim UE 282. If there is no potential victim UEdetected, the flow returns to step 1110 and the eNB continues to assignuplink channels to the aggressor UE without adjacent channelinterference restrictions.

If a potential victim UE is detected 1120, the co-scheduler allocates1130 a second set of subcarriers, subframes, or transmission powerparameters to the aggressor UE uplink channel. For example, the secondset 1140 excludes a sub-carrier from the first set that was nearest theadjacent frequency band. By reducing transmissions by the UE near thefrequency band edge, adjacent channel interference can be mitigated inthe adjacent band, and the potential victim UE may be able to properlyreceive signals on its downlink. As another example, the second set 1160results in a lower transmission power of the aggressor UE. Optionally,if the eNB is aware of which of the potential victim UE's receptionsubframes will overlap with the aggressor UE's transmission subframes,the second set can be limited 1150, 1170 to only those subframe portions(i.e., less than a complete subframe) that will potentially causeadjacent channel interference. This technique may be used to preventinterference with a PDCCH scheduled for the victim UE. Still further,the reduced set of subcarriers can be limited 1155, 1175 to completesubframes that will interfere with reception in the adjacent band by thevictim UE.

The flow returns to step 1120 to check whether the potential victim UEis still proximal to the aggressor UE. If the potential victim UE isstill nearby, the co-scheduler 1030 allocates 1130 another second set tothe aggressor UE. Note that each “second set” of step 1130 does not needto mimic any previous “second set” of step 1130. For example, see FIG. 3where the “second set” subcarrier allocations changes from one subframe320, 321 to the next. Additionally, although the various dimensions offrequency-and-time and power-and-time are separately described withrespect to FIGS. 3-7, these dimensions can be used in any combination.Thus, mitigation in frequency-and-power-and-time is contemplated, andthe time units may be in subframes or portions of subframes.

When the potential victim UE is no longer near the aggressor UE, theco-scheduler returns to allocating 1110 an uplink channel for theaggressor UE without regard to potential adjacent channel interference,and thus the entire frequency band and standard power control isavailable to allocate to the aggressor UE.

FIG. 12 shows an example of a time and frequency graph for multi-radiocoexistence for channel measurements such as Radio Resource Management(RRM) and/or Radio Link Management (RLM) measurements. In this example,the x-axis 1298 represents time and the y-axis represents frequency1299. A timing offset 1297 may be non-zero (as shown) or sub-framealigned (where T_(O)=0). Initially, a potential aggressor UE 281 isgiven a semi-persistent uplink grant at subframes 1210, 1220, 1230.Although the aggressor UE's uplink subframes 1210, 1220, 1230 do notcreate interference for a proximal victim UE's downlink grant onsubframe 1250, aggressor UE transmissions during subframe 1220 may causeinterference during a victim UE's measurement occasion 1260. In thissituation, a potential aggressor UE 281 does not transmit during aparticular assigned uplink subframe 1220 that overlaps with the victimUE's measurement occasion 1260. This allows the victim UE 282 taking RRMand/or RLM measurements during subframe 1260 in an adjacent band toobtain measurement metrics without interference from the nearbyaggressor UE 281.

A co-scheduler 1030 can instruct the aggressor UE 281 to not transmitduring subframe 1220, the aggressor UE 281 can decide autonomously tonot transmit during subframe 1220, or both approaches may be combined.Note that, technically, a transmitter is considered to be “nottransmitting” when its transmit power is below an off-level threshold,which is usually −50 dBm for LTE systems. In a situation where theco-scheduler 1030 instructs the aggressor UE 281 to not transmit duringa particular subframe, the co-scheduler 1030 instructs the aggressor UE281 to not transmit during subframe 1220 based on measurement gaps alsoscheduled by the co-scheduler for victim UE 1082. An exception to thesemi-persistent scheduling can be transmitted to the aggressor UE's eNBalong with the UE1 scheduling information 1045.

If the aggressor UE 281 decides by itself to not transmit duringsubframe 1220, it is because the UE2 scheduling information 1049 sent tothe aggressor UE's eNB includes measurement gap information, which isthen transmitted 1099 to the aggressor UE. Using its own schedulinginformation and the measurement gap scheduling information of the victimUE, the aggressor UE can determine that a particular semi-persistentuplink subframe 1220 conflicts with a victim UE measurement gap 1260 andcan avoid transmitting on that particular uplink subframe. If theaggressor UE 281 makes an autonomous decision, the aggressor UE 281 willreceive a NACK from its serving base station 1010 indicating that PUSCHdata was not received (due to the fact that no PUSCH data wastransmitted during that subframe 1220), and succeeding transmissions infuture subframes 1230 will provide opportunities for transmission ofPUSCH data. Note that the aggressor UE, for any particular sub-frame,can decide either to transmit or not-transmit on a particularsemi-persistent uplink subframe that is predicted to interfere withmeasurements at the victim UE 1082.

Yet another variation involves the co-scheduler 1030 transmitting bothUE1 scheduling information 1045 and UE2 scheduling information 1049 tothe aggressor UE's eNB for further transmission 1099 to the aggressor UE1081 along with instructions for the aggressor UE 1081 to not transmiton scheduled semi-persistent uplink sub-frames that overlap with UE2measurement gaps. In that situation, the aggressor UE makes it owndecision to not transmit during semi-persistently scheduled uplinksub-frames 1220 that overlap a victim UE's measurement gaps 1260, butthis decision is formulaic and the eNB 1010 can also make the samepredictions. Thus, when no PUSCH data is received from a particularuplink sub-frame 1220 that is predicted to interfere with measurementgaps 1260 at the victim UE 1082, the eNB 1010 may choose to not transmita NACK.

When the victim UE 1082 is no longer proximal to the aggressor UE 1081,as determined by the proximal interference assessor 1033, theco-scheduler 1030 can stop transmitting UE2 scheduling information 1049with measurement gap information and/or specific instructions tonot-transmit on a particular semi-persistently scheduled uplinksub-frame. Thus, a co-scheduler 1030 may also help reduce interferenceduring a victim UE's measurement gaps in addition to (or instead of)helping to reduce interference during a victim UE's downlink sub-frames.

FIG. 13 shows an example flow diagram 1300 at a co-scheduler for amethod for multi-radio coexistence during channel measurements. Thisflow diagram 1300 may be implemented at a co-scheduler, such as theco-scheduler 1030 shown in FIG. 10. Initially, the co-scheduler sends1310 a semi-persistent uplink grant to a first UE. Next, theco-scheduler checks 1320 whether the first UE (an aggressor UE) isoperating proximal to a second UE (a potential victim UE) on an adjacentband. If there is no potential victim UE near to the aggressor UE, thenthe flow returns to checking 1320 (perhaps after a waiting period, whichis not shown).

If a second UE is operating proximal to the first UE, the co-schedulercan take one of several coexistence actions 1340. As a first option, theco-scheduler may simply instruct 1350 the first UE to not-transmit oneor more periodic uplink transmissions (or not-transmit all uplinktransmissions) on a semi-persistently scheduled uplink sub-frame thatoverlaps (in time) with a RRM/RLM or other type of channel measurementby the victim UE 282 on an adjacent band. Because the co-schedulerassigns measurement gaps for the second UE, it can decide when to cancelpart or all of a particular semi-persistently scheduled uplinksub-frame.

Another option is to send 1360 the victim UE's scheduling informationincluding measurement gap information to the first eNB. The first eNBthen transmits at least the measurement gap information to the aggressorUE so that the aggressor UE can autonomously decide whether to nottransmit one or more periodic uplink transmissions during a particularsemi-persistently scheduled uplink sub-frame or mute an entiresemi-persistently scheduled uplink sub-frame. During this option, theaggressor UE's eNB does not know when the aggressor UE may choose tomute a persistently scheduled uplink sub-frame and will transmit a NACKto the aggressor UE in response to not-receiving a particular uplinksub-frame.

In addition to sending 1360 the victim UE's measurement gap informationto the first eNB, the co-scheduler may also send instructions 1365directing the aggressor UE to not-transmit one or more periodic uplinktransmissions or mute a semi-persistently scheduled uplink sub-framethat overlaps (in time) with a measurement gap of the second UE. Thus,although the aggressor UE determines which semi-persistently scheduleduplink sub-frames to reduce or mute, this timing can also be determinedby the aggressor UE's eNB. In this manner, the aggressor UE's eNB canavoid transmitting a NACK for a muted semi-persistently scheduled uplinksub-frame.

The flow returns to step 1320, possibly after a waiting period, todetect whether the two UEs are still proximal to each other. Note thatthe aggressor UE may be proximal to more than one victim UE and thecoexistence methods may be tailored to the specific combination ofaggressor and victim UEs as known by the co-scheduler.

As alluded to earlier, an alternative to suspending all uplinktransmissions in a semi-persistently granted subframe 1220 is to suspendone or more periodic uplink transmissions in a granted subframe 1220.Period uplink transmissions include Physical Uplink Control Channel(PUCCH), Sounding Reference Signal (SRS), and Uplink Shared Channel(UL-SCH) carrying semi-persistently scheduled transmissions. This allowsthe PUSCH data to be transmitted but provides less interference when thevictim UE 282 is taking measurements in overlapping subframe 1260 on anadjacent band 130.

Yet another alternative is to schedule measurement gaps for victim UEsto reduce overlapping transmissions from nearby transmitting UEs.Depending on the uplink channel assignments to the aggressor UE, thismay be quite feasible if there is a small number of potential aggressorUEs. For example, if the aggressor UEs were assigned uplink grantsduring subframes 1210, 1220, and 1230, the co-scheduler could schedule ameasurement gap for a victim UE anytime during subframe 1265 on theadjacent band 130.

FIG. 14 shows a further example of a time and frequency graph formulti-radio coexistence. In contrast to FIGS. 3, 5, and 12, the middlefrequency band 1430 is a paired downlink with a corresponding FDD uplink1440. In this situation, PDCCH interference 1415 occurs when anaggressor UE transmits on the FDD uplink band 110 (e.g., during subframe1420) while the victim UE is receiving in the downlink band 1430 (e.g.,during subframe 1431). The x-axis 1498 is time and the y-axis 1499 isfrequency, and the subframes on the first FDD pair of bands 110, 120 arenot aligned with the subframes of the second FDD pair of bands 1430,1440 as shown by the non-zero timing offset 1497.

As described previously, Physical Downlink Control Channel (PDCCH)resources and reference symbols (such as a cell-specific referencesymbol) are transmitted by a serving eNB 220 during the first few (1-3)symbols of a subframe. (Cell-specific reference symbols are transmittedin symbols 1 and 2, but are also transmitted in other symbols in thesubframe.) The PDCCH instructs its served UEs (e.g., victim UE 282)regarding its time and frequency allocation for the current downlinksubframe on a Physical Downlink Shared Channel (PDSCH) and for a futureuplink subframe on a Physical Uplink Shared Channel (PUSCH). If thePDCCH is not properly decoded, the victim UE 282 will have difficultyobtaining its physical channel data on the PDSCH and, due to a failureto decode the uplink grant, will not transmit its physical channel dataon the future PUSCH.

Usually, the PDCCH (at subframe n) includes uplink transmission grantinformation for a PUSCH four sub-frames 1460 into the future (atsubframe n+4). If the PDCCH is not properly decoded due to PDCCHinterference 1415, the PUSCH sub-frame 1460 will be wasted because thevictim UE is unaware that the PUSCH has been granted during thatsubframe 1460 and therefore will not transmit during that sub-frame1460.

The co-scheduler 1030 may be aware that the aggressor UE 281 may causePDCCH interference 1415 on a certain victim UE subframe 1431. Thisinformation can be used to mitigate interference in time and/orfrequency per FIG. 5, or the conflict information may be used to helpthe victim UE's eNB shift the PDCCH 1431 assigning the PUSCH subframe1460 to a subframe 1433, 1435 that is less likely to experienceinterference from a proximally-located aggressor UE 281.

If the PDCCH assignment shifts to a different subframe 1433, 1435, thePDCCH uplink transmission grants will no longer be transmitted foursubframes 1481 prior to the granted PUSCH subframe 1460. Instead, thegranted PUSCH subframe 1460 may be five subframes 1483 after the PDCCHassignment or three subframes 1485 after the PDCCH assignment. Althoughthe PDCCH assignment shift is shown as +/−one subframe, more significantshifts are possible. In order to signal the PDCCH assignment shift, thevictim UE's eNB may transmit an indicator, referred to here as aScheduling Delay Index (SDI), to advance or delay an uplink PUSCH grantrelative to the PDCCH uplink transmission grant.

FIG. 15 shows an example flow diagram 1500 for a method for multi-radiocoexistence using a scheduling delay index. In this flow diagram, aco-scheduler looks for conflicts between a victim UE's PDCCH grant ofuplink resources and an adjacent-band aggressor UE's uplinktransmissions.

Initially, the co-scheduler schedules 1510 uplink wireless resources forall UEs that it controls. Specifically, the co-scheduler schedules 1513uplink resources to a potential aggressor UE such as UE 281 operating onpaired FDD uplink frequency band 110. Also, the co-scheduler schedules1516 uplink resources to a potential victim UE operating in an adjacentfrequency band such as UE 282 operating in FDD downlink band 1430 shownin FIG. 14.

Next, the co-scheduler detects 1520 whether the UE1 and UE2 areoperating proximal to each other. If the UEs are not proximal to oneanother, the flow returns to scheduling 1510 without regard toproximal-UE interference. If the UEs are proximal to each other, theco-scheduler looks for conflicts 1530 between the PDCCH grant of UE2 andthe aggressor UE1's uplink wireless resource grants. As mentionedpreviously, a standard PDCCH uplink assignment will occur four subframesprior to the corresponding uplink PUSCH subframe.

If the co-scheduler predicts 1530 no conflict between the UE2's PDCCHreception and a proximal aggressor UE1's uplink transmissions, the flowreturns to scheduling 1510. If there is a foreseeable conflict 1530, theco-scheduler recommends 1540 a scheduling delay index (or indices) tothe victim UE's eNB to advance or delay the victim UE's PDCCH signalingthat provides uplink transmission grants for a future PUSCH by thatvictim UE. The eNB may choose any one of the suggested SDIs, encode thevictim UE's future PUSCH assignment in a PDCCH to the victim UE, andtransmit the shifted PDCCH along with the SDI to the victim UE.Alternately, the eNB may not shift the PDCCH and risk potentialinterference by an adjacent aggressor UE.

The flow then returns to scheduling 1510 UE1 and UE2 uplink wirelessresources and checking 1520 for proximal UEs that may interfere witheach other. This method mitigates PDCCH interference by shifting thePDCCH assignment of an uplink wireless resource to reduce interferencefrom a proximal aggressor UE's uplink transmission. Because the PDCCHassignment is shifted to a different subframe, a SDI is used to informthe victim UE that the PUSCH grant has moved to a different subframerelative to the PDCCH assignment subframe. Thus, the PDCCH assignmentsubframe, which is usually four subframes prior to the PUSCH grant, isno longer four subframes ahead; and the SDI indicates how the PDCCHassignment subframe has moved.

Because PDCCH is sent every subframe, the interfered-with PDCCH insubframe 1431 will no longer contain information vital to the PUSCHgrant in subframe 1460. Thus, by moving (advancing or delaying) a PDCCHtransmission to a victim UE from a regularly-scheduled subframe (e.g.,subframe n 1431) that is forecasted to be subject to adjacent channelinterference by a proximal aggressor UE to a subframe (e.g., subframen−1 1433 or subframe n+1 1435) that is not expected to experience thisinterference, the PDCCH can benefit from coexistence techniques in thesituation of adjacent channel interference caused by the proximity of anaggressor UE.

Thus, a co-scheduler may control an aggressor UE in transmission power,time, and frequency to mitigate UE-to-UE adjacent carrier systeminterference when a victim UE is receiving nearby. By complying with thetransmission power, time, and frequency parameters as directed by theco-scheduler, the aggressor UE may reduce desense of the proximal victimUE's receiver. The co-scheduler can also compensate for some of thespectrum inefficiencies caused by the interference mitigation byintelligent scheduling of several UEs, some being proximal to the victimUE and others being distant from the victim UE. Meanwhile, the aggressorUE may implement two power control loops to reduce interference when avictim UE is receiving (or taking channel measurements) versus when thevictim UE is transmitting.

While this disclosure includes what are considered presently to be theembodiments and best modes of the invention described in a manner thatestablishes possession thereof by the inventors and that enables thoseof ordinary skill in the art to make and use the invention, it will beunderstood and appreciated that there are many equivalents to theembodiments disclosed herein and that modifications and variations maybe made without departing from the scope and spirit of the invention,which are to be limited not by the embodiments but by the appendedclaims, including any amendments made during the pendency of thisapplication and all equivalents of those claims as issued.

For example, although LTE systems have been described in detail,teachings from this specification may be applied to TDMA/GSM systems,other OFDMA systems, and other wireless access technologies. Also,although wide area networks have been implied, teachings from thisspecification may be applied to local area networks and personal areanetworks. Accordingly, the specification and figures are to be regardedin an illustrative rather than a restrictive sense, and all suchmodifications are intended to be included within the scope of presentteachings.

The benefits, advantages, solutions to problems, and any element(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeatures or elements of any or all the claims. The invention is definedsolely by the appended claims including any amendments made during thependency of this application and all equivalents of those claims asissued.

It is further understood that the use of relational terms such as“first” and “second”, “top” and “bottom”, and the like, if any, are usedsolely to distinguish one from another entity, item, or action withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities, items or actions. Much of the inventivefunctionality and many of the inventive principles are best implementedwith or in software programs or instructions. It is expected that one ofordinary skill, notwithstanding possibly significant effort and manydesign choices motivated by, for example, available time, currenttechnology, and economic considerations, when guided by the concepts andprinciples disclosed herein will be readily capable of generating suchsoftware instructions and programs with minimal experimentation.Therefore, further discussion of such software, if any, will be limitedin the interest of brevity and minimization of any risk of obscuring theprinciples and concepts according to the present invention.

The terms “comprises,” “comprising,” “has”, “having,” “includes”,“including,” “contains”, “containing” or any other variation thereof,are intended to cover a non-exclusive inclusion, such that a process,method, article, or apparatus that comprises, has, includes, contains alist of elements does not include only those elements but may includeother elements not expressly listed or inherent to such process, method,article, or apparatus. An element proceeded by “comprises . . . a”, “has. . . a”, “includes . . . a”, “contains . . . a” does not, without moreconstraints, preclude the existence of additional identical elements inthe process, method, article, or apparatus that comprises, has,includes, contains the element. The terms “a” and “an” are defined as“one or more” unless explicitly stated otherwise herein. The terms“substantially”, “essentially”, “approximately”, “about” or any otherversion thereof, are defined as being close to as understood by one ofordinary skill in the art, and in one non-limiting embodiment the termis defined to be within 10%, in another embodiment within 5%, in anotherembodiment within 1% and in another embodiment within 0.5%. The term“coupled” as used herein is defined as connected, although notnecessarily directly and not necessarily mechanically. A device orstructure that is “configured” in a certain way is configured in atleast that way, but may also be configured in ways that are not listed.

As understood by those in the art, a mobile device includes a processorthat executes computer program code to implement the methods describedherein. Embodiments include computer program code containinginstructions embodied in tangible media, such as floppy diskettes,CD-ROMs, hard drives, or any other computer-readable storage medium,wherein, when the computer program code is loaded into and executed by aprocessor, the processor becomes an apparatus for practicing theinvention. Embodiments include computer program code, for example,whether stored in a storage medium, loaded into and/or executed by acomputer, or transmitted over some transmission medium, such as overelectrical wiring or cabling, through fiber optics, or viaelectromagnetic radiation, wherein, when the computer program code isloaded into and executed by a computer, the computer becomes anapparatus for practicing the invention. When implemented on ageneral-purpose microprocessor, the computer program code segmentsconfigure the microprocessor to create specific logic circuits.

Moreover, it will be appreciated that some embodiments may be comprisedof one or more generic or specialized processors (or “processingdevices”) such as microprocessors, digital signal processors, customizedprocessors and field programmable gate arrays (FPGAs) and unique storedprogram instructions (including both software and firmware) that controlthe one or more processors to implement, in conjunction with certainnon-processor circuits, some, most, or all of the functions of themethod and/or apparatus described herein. Alternatively, some or allfunctions could be implemented by a state machine that has no storedprogram instructions, or in one or more application specific integratedcircuits (ASICs), in which each function or some combinations of certainof the functions are implemented as custom logic. Of course, acombination of the two approaches could be used.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter.

We claim:
 1. A method in a wireless terminal comprising: determining a first power value for a first set of time periods of a subcarrier frequency based on at least one first transmission power control parameter; determining a second power value for a second set of time periods of the subcarrier frequency based on at least one second transmission power control parameter; determining whether a particular time period belongs to the first set of time periods or the second set of time periods; if the particular time period belongs to the first set of time periods, transmitting on the subcarrier frequency in the particular time period with a transmission power based on the first power value; and if the particular time period belongs to the second set of time periods, transmitting on the subcarrier frequency in the particular time period with a transmission power based on the second power value.
 2. The method of claim 1 wherein the first set of time periods and the second set of time periods are non-overlapping in time.
 3. The method of claim 1 wherein the first set of time periods and the second set of time periods are partially overlapping in time.
 4. The method of claim 1 wherein the first set of time periods corresponds to use of a first RAT and the second set of time periods corresponds to use of a second RAT.
 5. The method of claim 1 further comprising: transmitting on the subcarrier frequency in the particular time period using a first component carrier wherein the first power value and the second power value correspond to the first component carrier.
 6. The method of claim 1 further comprising: receiving the at least one first transmission power control parameter and the at least one second transmission power control parameter from a serving base station.
 7. The method of claim 6 wherein the at least one second transmission power control parameter includes at least a power offset value and wherein the determining a second power value comprises: using the power offset value and the at least one first transmission power control parameter to determine the second power value.
 8. The method of claim 7, wherein the power offset value is one or more of: a transmission power offset value, an offset value to an uplink power control parameter, and a Maximum Power Reduction (MPR) offset value.
 9. The method of claim 1, wherein the at least one first transmission power control parameter includes a first Maximum Power Reduction (MPR) and the at least one second transmission power control parameter includes a second Maximum Power Reduction (MPR).
 10. The method of claim 1 wherein transmitting comprises: transmitting one or more of a physical uplink shared channel, a physical uplink control channel, a sounding reference signal, or a demodulation reference signal.
 11. The method of claim 1 wherein determining the first power value comprises: determining the first power value based on ${P_{{PUSCH},{{loop}\; 1}}(n)} = {\min\left\{ \begin{matrix} {\mspace{140mu}{{P_{CMAX}(n)},}} \\ {{10{\log_{10}\left( {M_{PUSCH}(n)} \right)}} + P_{{O\_ PUSCH},{{loop}\; 1}} +} \\ {\mspace{25mu}{{\alpha_{{loop}\; 1} \cdot {PL}} + {\Delta_{{TF},{{loop}\; 1}}(i)} + {f_{{loop}\; 1}(i)}}} \end{matrix} \right\}}$ wherein P_(CMAX)(n) is a configured maximum transmit power applicable to subframe n, M_(PUSCH)(n) is a bandwidth of a transmission in subframe n, P_(O) _(—) _(PUSCH, loop 1) is an open loop power offset value configured by higher layers, α_(loop 1) is a fractional power control coefficient configured by higher layers, PL is a path loss value associated with a wireless link between the wireless terminal and its serving base station, Δ_(TF, loop 1)(i) is a power control delta, and f_(loop 1)(i) is a power adjustment term, wherein i is a number of subframes over which power offsets derived from transmit power control (TPC) commands were accumulated and wherein the at least one first transmission power control parameter includes at least P_(O) _(—) _(PUSCH, loop 1) , α_(loop 1) and Δ_(TF, loop 1)(i).
 12. A method of claim 1 further comprising: determining a first power headroom report associated with the transmitting based on the first power value if the particular time period belongs to the first set of time periods; determining a second power headroom report associated with the transmitting based on the second power value if the particular time period belongs to the second set of time periods; and transmitting at least one power headroom report to a serving base station of the wireless terminal.
 13. A method in a wireless terminal comprising: determining a first power value for a first set of time periods of a subcarrier frequency based on at least one first transmission power control parameter; determining a second power value for a second set of time periods of the subcarrier frequency based on at least one second transmission power control parameter; if a transmission over a particular time period is based on the first power value, determining a first power headroom report associated with the transmission; if the transmission over the particular time period is based on the second power value, determining a second power headroom report associated with the transmission; and transmitting at least one power headroom report to a serving base station of the wireless terminal.
 14. The method of claim 13 wherein the first set of time periods and the second set of time periods are non-overlapping in time.
 15. The method of claim 13 wherein the first set of time periods and the second set of time periods are partially overlapping in time.
 16. The method of claim 13 further comprising: receiving the at least one first transmission power control parameter and the at least one second transmission power control parameter from a base station.
 17. The method of claim 16 wherein the at least one second transmission power control parameter includes at least a power offset value and wherein the determining a second power value comprises: using the power offset value and the at least one first transmission power control parameter to determine the second power value.
 18. The method of claim 17, wherein the power offset value is one or more of a transmission power offset value, an offset value to P_(O) _(—) _(PUSCH), an offset of a P_(O) _(—) _(PUSCH) component, PL offset, Δ_(TF) offset, or a Maximum Power Reduction (MPR) offset value.
 19. The method of claim 13 wherein the transmitting at least one power headroom report comprises: transmitting the at least one power headroom report applicable to a first component carrier wherein the first power value and the second power value correspond to the first component carrier.
 20. The method of claim 13, wherein the at least one first transmission power control parameter includes one or more of: a first P_(O) _(—) _(PUSCH), a first P_(O) _(—) _(PUSCH) component, a first offset to PL, a first Δ_(TF), or a first Maximum Power Reduction (MPR); and the at least one second transmission power control parameter includes one or more of: a second P_(O) _(—) _(PUSCH), a second P_(O) _(—) _(PUSCH) component, a second offset to PL , a second Δ_(TF), or a second Maximum Power Reduction (MPR).
 21. The method of claim 13, wherein the transmitting comprises: transmitting one or more of a physical uplink shared channel, a physical uplink control channel, a sounding reference signal, or a demodulation reference signal.
 22. The method of claim 13, wherein determining the first power value comprises: determining the first power value based on PH _(loop 1)(n)=P _(CMAX)(n)−{10 log ₁₀(M _(PUSCH)(n))+P _(O) _(—) _(PUSCH,loop 1)+α_(loop 1) ·PL+Δ _(TF,loop 1)(i)+f _(loop 1)(i)} wherein PH_(loop 1)(n) is the first power value, P_(CMAX)(n) is a configured maximum transmit power applicable to subframe n, M_(PUSCH)(n) is a bandwidth of the transmission in subframe n, P_(O) _(—) _(PUSCH, loop 1) is an open loop power offset value configured by higher layers, α_(loop 1) is a fractional power control coefficient configured by higher layers, PL is a path loss value associated with a wireless link between the wireless terminal and its serving base station, Δ_(TF, loop 1)(i) is a power control delta, and f_(loop 1)(i) is a power adjustment term, wherein i is a number of subframes over which power offsets derived from transmit power control (TPC) commands were accumulated and wherein the at least one first transmission power control parameter includes at least P_(O) _(—) _(PUSCH, loop 1) , α_(loop 1) and Δ_(TF, loop 1)(i).
 23. The method of claim 13 wherein the transmitting comprises: receiving a power headroom report transmission instruction from the serving base station; and transmitting the at least one power headroom report in compliance with the power headroom report transmission instruction. 